I personally dislike the idea of showing too much error information to the user, because most users won't be interested in a stacktrace (well...except maybe hack3rz).
But on the other hand, as a developer I would like to see the whole stacktrace quick without digging into some logfiles on the server.
So in order to hide details, you could throw up the exception, define a error-page in your web.xml
and in your error.jsp comment out the stacktrace by putting something like this (uses JSTL):
So you just have to view the webpages sourcecode to see the full stacktrace, and the 'normal' user won't be confused by too much information
HTH
Jans